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Proton

This simplistic model of an atom shows protons as red spheres in the central nucleus. This model is NOT to scale; to match the scale of the nucleus the electrons (yellow) should be much smaller and much further away from the nucleus. Original artwork by Windows to the Universe staff (Randy Russell).

A proton is one of the most important types of subatomic particles. Protons
combine with electrons
and (usually) neutrons to make atoms.

Protons are nearly the same size as neutrons and are much larger than electrons.
A proton has a mass about 1,836 times greater than the mass of an electron,
but the masses of protons and neutrons differ from each other by less than
one percent. A proton has a mass of 1.6726 x 10-24 grams.

Protons have a positive electrical charge, which is sometimes called the elementary
charge or fundamental charge or a charge of +1. Electrons have a charge of
the same strength but opposite polarity, -1. The fundamental charge has a strength
of 1.602 x 10-19 coulomb.

The nucleus of an atom is a combination of roughly equal numbers of protons
and neutrons held together by the strong
nuclear force. Clouds of electrons
orbit the nucleus, attracted by the positive charges of the protons.

Protons are baryons, a class of subatomic particles that also includes neutrons.
Protons are composed of two up quarks and one down quark.

A single electron orbiting a single proton is a simple hydrogen atom, the
most abundant element in the Universe. Such hydrogen atoms often have their
electron stripped away in a process called ionization, which leaves a lone
proton. Such lone protons, also called hydrogen ions (H+), are very
common. Because of their charges, these protons can be accelerated by electrical
or magnetic fields to high energies, and can thus become a dangerous form of
particle
radiation.

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